Recent versions of copying apparatus have various extra capabilities including those for binding margins, zoomed magnification and reduction, mathematic calculation and frame erasure. For each of such extra capabilities, there are different requirements such as the widths to be selected for binding margins so as to meet the growing demands from the users. The provision of such additional capabilities and to meet such different requirements, however, the duplicating apparatus necessitates an increased number of switches and controls which lead to added complexity of the control panel through which the operator manually controls the apparatus. The increase in the number of switches and controls further results in the complexity of hardware and requires a microprocessor with an increased capacity and an increased number of input and output ports. All these add to the production cost of duplicating machines being developed.